Aerosol Optical Depth of the Main Aerosol Species over Italian Cities Based on the NASA/MERRA-2 Model Reanalysis

Rizza, Umberto; Mancinelli, Enrico; Morichetti, Mauro; Passerini, G.; Virgili, Simone

doi:10.3390/atmos10110709

Cited by 24 publications

(10 citation statements)

References 39 publications

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“…This climatology is now obsolete. Since the beginning of the century, AOD in Europe generally decreased by amount depending on the location but sometimes as much as 0.05 for average AOD typically about 0.2 (Filonchyk et al 2019;Rizza et al 2019). The Kinne climatology may thus overestimate AOD for recent years.…”

Section: Aerosol Optical Propertiesmentioning

confidence: 99%

Accuracy of satellite-derived solar direct irradiance in Southern Spain and Switzerland

Vuilleumier

Meyer

Stöckli

et al. 2020

International Journal of Remote Sensing

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We present a validation study of direct normal irradiance (DNI) estimates from HelioMont with ground-based measurements from two European sites for the year 2015. The HelioMont algorithm infers irradiance with data from the Meteosat Second Generation Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument as the primary source of information on clouds, and data from models or reanalysis for other influential input parameters. The validation sites are the Plataforma Solar de Almería (PSA), a solar power research facility in Southern Spain characterized by arid conditions and the Swiss Baseline Surface Radiation Network (BSRN) site of Payerne, characterized by a much more frequent cloud coverage. Our analysis shows the importance of separately evaluating the quality of (1) the clear-sky irradiance computation and (2) the determination of the cloud effect. We also specifically investigate the cloud modification factor (CMF) using a validation CMF derived from ground-based data, giving us more insight into event-by-event agreement between HelioMont estimates and measured irradiances. The clear-sky HelioMont DNI uncertainty is mainly influenced by the aerosol optical depth (AOD) input data. Using the original AOD input (a 2008 climatology based on data from the Aerosol Comparisons between Observations and Models project) leads to large negative biases of 115 W m −2 to 145 W m −2. Using AOD from the Copernicus Atmosphere Monitoring Service (CAMS) allows reducing these biases to 15 W m −2 to 25 W m −2 (2% to 3%) with a dispersion of ±12% to ±15%, which is the HelioMont clearsky DNI expanded uncertainty when using CAMS AOD. Using ground-measured AOD reduces this uncertainty to ±5% to ±6.5%, which is probably the limit of what is achievable with HelioMont. For all-sky comparisons, mean biases were between about −5 W m −2 and 55 W m −2 (depending on AOD input and station), while the root-mean-square deviation (RMSD) was between about 175 W m −2 and 195 W m −2. Our validation method yielded ARTICLE HISTORY

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Section: Aerosol Optical Propertiesmentioning

confidence: 99%

Accuracy of satellite-derived solar direct irradiance in Southern Spain and Switzerland

Vuilleumier

Meyer

Stöckli

et al. 2020

International Journal of Remote Sensing

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“…It has been estimated that 10% of the Saharan dust amount is transported across the Mediterranean Sea to Europe [6,7] in episodic storms or following periodic patterns [8,9]. In recent studies [10,11], it was reported an average contribution between 30% and 40% to the optical depth over different cities in southern Europe.…”

Section: Introductionmentioning

confidence: 99%

Investigation of an Intense Dust Outbreak in the Mediterranean Using XMed-Dry Network, Multiplatform Observations, and Numerical Modeling

et al. 2021

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The Weather Research and Forecasting (WRF) model with online coupled chemistry (WRF-Chem) is applied to study an intense Saharan dust outbreak event affecting the Italian peninsula in 15 and 16 April, 2018. According to the MODIS retrievals, this intrusion was characterized by an intense aerosol optical depth (AOD) peak value in the southern Mediterranean. Measurements within the Dry Deposition Network Across the Mediterranean (XMed-Dry) are compared with the output of the WRF-Chem model. XMed-Dry samples from Lecce (Italy), Athens (Greece) and San Lawrenz/Gozo (Malta) were analysed with respect to aerosol particle size distribution, relative dust contribution, and composition. The discrepancy between the model and measured deposition indicate the need to formulate in WRF-Chem more sophisticated deposition schemes, this will need to evaluate the sensitivity of the results to the precise particle size limits chosen for the aerosol model. Moreover, satellite retrievals from MODIS sensors elaborated with the MAIAC algorithm, Aeronet stations, and measurements of at the selected sites were also considered. In a numerical domain that spans the Mediterranean and the northern Saharan desert, two different dust emission schemes, namely Gocart-AFWA and the Shao-2001, were tested and compared with multiplatform observations for simulation period covering the dust outbreak. Actual results indicate that both emission schemes would benefit from replacing the static erodibility map and soil particle distribution with remote sensed and in-situ observational data.

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“…Thus, atmospheric parameters may affect UVB and UVA irradiance in a different way at different locations (e.g., Fountoulakis et al, 2020). Recent studies have shown that atmospheric parameters which affect significantly solar UV radiation, such as clouds (Manara et al, 2016;Manara et al, 2015;Mateos et al, 2011;Pfeifroth et al, 2018) and aerosol (Orza and Perrone, 2015;Rizza et al, 2019;Di Ianni et al, 2018;Putaud et al, 2014;Masiol et al, 2017;di Sarra et al, 2008) have changed in Italy in the last decades, either on a regional or on a country scale. Although in Italy long-term continuous solar spectral UV (Diémoz et al, 2011) and total ozone measurements (Siani et al, 2018) are available from different stations across the country, they have never been used to study the long-term changes of UV irradiance at the surface, and how they are affected by changes in total ozone.…”

Section: Introductionmentioning

confidence: 99%

Variability and trends of the surface solar spectral ultraviolet irradiance in Italy: a possible influence of lower and upper stratospheric ozone trends

Fountoulakis

Diémoz

Siani

et al. 2021

Preprint

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Abstract. In this study the short- and long-term variability of the surface spectral solar ultraviolet (UV) irradiance are investigated over Italy using high quality ground based measurements from three sites located at quite different environmental conditions, and covering the full latitudinal extent of the Italian territory: Aosta (45.7° N, 7.4° E, 570 m a.s.l.), Rome (41.9° N, 12.5° E, 75 m a.s.l.), and Lampedusa (35.5° N, 12.6° E, 50 m a.s.l.). The variability of the irradiances at 307.5 nm, 324 nm, and of the ratio between the 307.5 nm and the 324 nm irradiances were investigated with respect to the corresponding variability in total ozone and the geopotential height at 250 hPa (GPH). The study was performed for two periods: 2006–2020 for all stations, and 1996–2020 only for Rome. A statistically significant correlation between the GPH and total ozone monthly anomalies was found for all stations and all seasons of the year. A corresponding statistically significant correlation was also found in most cases between the GPH and the 307.5 nm irradiance monthly anomalies. The correlation between GPH anomalies at different sites was statistically significant, possibly explaining the strong and significant correlation between the total ozone monthly anomalies at the three sites. A statistically significant decrease of total ozone, of ~0.1 %/year was found for Rome for the period 1996–2020, which however did not induce increasing trends in irradiance at 307.5 nm (neither increasing trends in the ratio between the 307.5 nm and the 324 nm irradiances) at SZA = 67°. Further analyses revealed positive trends in the ratio and the 307.5 nm irradiance at smaller solar zenith angles (SZA), which can be attributed to the fact that total ozone decrease is driven by a decrease in the lower stratosphere while upper stratospheric ozone increases, and the effect of changes of upper stratospheric ozone becoming disproportionately larger for increasing SZA. It was also showed that long-term changes in total ozone follow changes in GPH, which is an additional indication that negative trends in total ozone are mainly driven by changes in lower stratospheric ozone. An anti-correlation between the GPH long-term changes and total ozone was also evident for all stations in 2006–2020. Positive trends in UV irradiance for this latter period which were possibly driven by changes in clouds and/or aerosols were found for Rome and Aosta. This study clearly points out the significance of dynamical processes which take place in the troposphere for the variability of total ozone and surface solar UV irradiance.

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Aerosol Optical Depth of the Main Aerosol Species over Italian Cities Based on the NASA/MERRA-2 Model Reanalysis

Cited by 24 publications

References 39 publications

Accuracy of satellite-derived solar direct irradiance in Southern Spain and Switzerland

Accuracy of satellite-derived solar direct irradiance in Southern Spain and Switzerland

Investigation of an Intense Dust Outbreak in the Mediterranean Using XMed-Dry Network, Multiplatform Observations, and Numerical Modeling

Variability and trends of the surface solar spectral ultraviolet irradiance in Italy: a possible influence of lower and upper stratospheric ozone trends

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